Material-screening sampler



May 12, 1970 R. L. VAUGHN E L 3,511,100

MATERIAL-SCREENING SAMPLER 2 SheetsSheet 1 Filed NOV. 18, 1968 INVENTORS ROGER L. VAUGHN JOHN F. BAUM W W ATTORNEYS y ,197o R. L. VAUGHN ETAL 3,511,100

MATERIAL-SCREENING SAMPLER Filed Nov. 18, 1968 2 Sheets-Sheet 2 INVENTORS ROGER L. VAUGHN JOHN F. BAUM BY W W AT TORNE Y5 United States Patent 3,511,100 MATERIAL-SCREEN IN G SAMPLER Roger L. Vaughn, Hurley, and John F. Baum, Silver 'City, N. Mex., assignors to Kennecott Copper Corporation, New York, N.Y., a corporation of New York Filed Nov. 18, 1968, Ser. No. 776,322 Int. Cl. G01n J/20 U.S. Cl. 73-423 7 Claims ABSTRACT OF THE DISCLOSURE Apparatus for periodically sampling a flowing stream of material. The apparatus screens out trash and other tramp material from the stream during the taking of the samples, and automatically cleans the screen following the taking of each sample. The screen is pivotally attached to the discharge end of a conduit, which supplies the stream of material and is shifted from side to side to discharge alternately into a sample receiver and a reject receiver. The screen is so mounted as to be tilted away from the discharged material and to have its travel abruptly stopped over the reject receiver, thereby dislodging and dumping tramp material caught by the screen.

BACKGROUND OF THE INVENTION Field The invention relates to mechanisms and systems for taking samples periodically from flowing streams of material, such as metallurgical pulps subjected to continuous stream assaying procedures, e.g. X-ray fluorescence.

State of the art It has been customary practice to take samples of a metallurgical pulp for X-ray fluorescence by diverting a sample stream of the pulp from the main stream and flowing it through a screen into a sample tank arranged for pulp overflow so as to maintain a constant head of pulp in the tank. The screen has been kept clean by a rotating brush. This has not been satisfactory, both because of the difliculty of obtaining representative samples and because of excessive wear on the brush and on the screen. Although a conduit supplying a flowing stream of material for various purposes has heretofore been shifted in position so as to periodically discharge into one or the other of side-by-side receivers, so far as applicants are aware this has not been coupled with screening mechanism for screening the flow and with provision for shaking off r trash accumulated on the screen.

SUMMARY OF THE INVENTION In the making of the invention, a principal purpose was to provide a low-cost sampling system that would maintain a constant feed flow, be free of segregation, and would remove tramp material from a varying source flow.

The sampling apparatus comprises a material-receiving tank divided into side-by-side, usually two, receiving compartments, one being adapted to receive and to pass on flowing material supplied thereto from a shiftable conduit and the other being adapted to accumulate therein a sample of the flowing material when the conduit is shifted thereto from the first i.e. sample-reject compartment. Shifting of the conduit to and from the sample compartment is preferably accomplished by an electrically, pneumatically, or otherwise powered device under the control of means arranged to sense the level of accumulated material in the sample compartment. The conduit, which is usually a flexible or hinged pipe, carries a screen at its discharge end pivotally attached to the tank and to the conduit so as to be in generally horizontal,

screening position over the sample compartment when the pipe is positioned for discharge thereinto and so as to be brought into an upright position and stopped abruptly to dislodge and dump trash material therefrom when the conduit is positioned for discharge into the sample-reject compartment.

Although the apparatus of the invention was conceived and constructed primarily for use in a material sampling system, embodiments thereof may well be useful in a variety of other situations where alternate screening and non-screening of a flowing stream of material is required.

The apparatus is described in detail and is illustrated in the accompanying drawings with respect to specific constructions presently contemplated as the best mode of carrying out the invention in actual practice.

THE DRAWINGS In the drawings:

FIG. 1 is an isometric view of the apparatus as installed in a sampling system for periodically diverting portions of a metallurgical pulp to X-ray fluorescence analysis, the material-supplying conduit being shown in normal, sample-reject, screen-dumping position, and the view including a wiring diagram of a typical electrical control circuit for automatic operation;

FIG. 2, a vertical section taken on the line 22 of FIG. 1 and drawn to a slightly smaller scale;

FIG. 3, a view corresponding to that of FIG. 2 but showing the apparatus in sample-receiving and samplescreening position;

FIG. 4, a fragmentary isometric view of the screen per se drawn to a larger scale; and

FIG. 5, a fragmentary view corresponding to part of FIG. 2 but showing a different mounting for the screen assembly.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS In the form illustrated in FIGS. 1-4, the apparatus of the invention is designed especially for taking samples periodically from a flowing stream of metallurgical pulp and sending such samples to X-ray fluorescence assaying equipment in a continuous stream. As shown, it comprises a tank 10 formed as two side-by-side compartments 10a and 10b with an intermediate wall portion in common, see FIGS. .2 and 3, midway between the compartments. The tank is mounted in an open structural framework 11 for receiving, in one or the other compartment, a stream of metallurgical pulp supplied by a conduit in the form of a pipe 12 having a discharge end portion 12a that is flexibly and therefore hingedly attached to the main conduit by means of a length of hose or other flexible tubing 13.

The discharge end portion 12a of the conduit pipe 12 is normally positioned over tank compartment 10a to discharge the stream of flowing material thereinto, but is adapted, by reason of the flexible portion 13, to be swung sidewardly over compartment 10b to discharge the stream thereinto for sampling purposes. Conduit end portion 12a may be switched from side-to-side manually by a workman stationed to observe conditions in sample compartment 10b, but is preferably attached by means of a collar 14 to the otherwise free end of a piston rod 15, FIG. 3, projecting from a hydraulic or pneumatic actuating cylinder '16, for power switching from the sample-reject compartment 100 to the sample compartment 10b.

Pivotally attached to the lower, discharge end of conduit end portion 12a, by means of a bail-like yoke 17 is a screening assembly 18, see particularly FIG. 4, made up of a set of two flat and rectangular screens 19 and 20 mounted in a frame 21. Yoke 17 is pivotally attached to opposite sides of frame 21 intermediate the ends thereof.

Screening assembly 18 is also pivotally attached at one of its ends to tank near intermediate wall portion 100 thereof so as to be swung from a normal upright position, FIGS. 1 and 2, at one side of the stream discharging into sample-reject compartment 10a of the tank, to a generally horizontal, screening position, FIG. 3, across the stream discharging into sample compartment 10b of the tank, and vice versa. As illustrated, the pivotal connection is made by means of a pivot pin extending through opposing walls of the tank and through depending ears 21a at respectively opposite sides of screen frame 21.

Mounted as it is, it can be seen that screen assembly 18 is brought to an abrupt halt in upright position over sample-reject compartment 10a of the tank on its return travel from its sample-screening position over sample compartment 10b of the tank. Introduction of motivating hydraulic or pneumatic fluid into power cylinder 16 through supply line 22 from main supply line 23 by way of solenoid-operated control valve 24 when conduit end portion 12a and screening assembly 18 are in the positions shown in FIG. 3 causes such conduit end portion and screen assembly to be rapidly moved to the opposite side of the tank and to be abruptly halted in the positions shown in FIG. 2 when piston rod 15 reaches the end of its retraction stroke. If the apparatus is constructed for manual rather than power actuation, power cylinder 16 will be replaced by an abutment stop for conduit end portion 12a so a similar abrupt halt will be assured. In either event, the abrupt halting of travel of the screening assembly will result in shaking the intake surfaces of the screens 19 and 20 free of oversize and tramp material retained thereon and will effect dumping of such material from the lower ends 19a and 20a of the respective screens into the sample-reject compartment 10a of the tank.

It should be realized that other mounting arrangements could be used for the screen assembly. For example, as shown in FIG. 5, a screening assembly 25, without depending mounting ears but otherwise similar to the screening assembly 18, has one end pivotally mounted by means of a pivot pin 26 extending between bracket hooks 27 hung from the top of the tank at respectively opposite sides thereof. This permits lifting of the screen assembly, together with the bracket hooks, from the tank when desired and does not require penetration of the tank walls by the pivot pin. Moreover, in this embodiment of the invention the arrangement is such that link 28 brings the screening assembly smartly against the conduit end portion 29 in the upright dumping position to jolt loose any material caught and retained by the screens. Thus, the screening assembly is brought to an abrupt halt by striking the conduit end portion as an abutment stop, rather than by the end of the stroke of the power cylinder 30.

Material received by such sample-reject compartment of the tank passes on through and out by way of pipe 31 to suitable processing operations, while screened samples of the feed material received by sample compartment 10b accumulate in such compartment to an extent predetermined either by the operator, in manually controlled apparatus, or by pulp-level control instrumentalities in automatically controlled apparatus such as that shown. In either instance, however, there is a continuous flow from the sample-receiving compartment to standard analytical equipment (not shown) by way of the relatively attenuate pipe 32.

Although electrical probes 33 are shown as pulp-level sensing means in the illustrated embodiment, any suitable control instrumentalities and system may be utilized for controlling operation of solenoid valve 24 in accordance with the quantity of material in sample compartment 10b of the tank, so the material in such compartment will neither overflow nor become exhausted at any time during operation of the system. Typical electrical control circuitry for operating solenoid valve 24 in accordance with signals from probes 33 is illustrated by the circuit diagram portion of FIG. 1.

Referring to this circuit diagram, the probes 33 comprise a low lever probe 33a and a high level probe 33b with a common probe connection 33c to ground. Power is supplied to the circuit from any suitable supply of same, typically a 24 volt line 34. The low probe is connected to a latching circuit 35 by Way of resistance R1, transistor T1, and resistance R2, while the high probe is connected to such latching circuit by way of resistance R3, transistor T2, and resistance R4. Power is supplied to the low probe circuit through resistors RS and R6, and to the high probe circuit through resistors R7 and R8. In each instance, when the probe is touched by liquid, conductivity is sensed through the particular transistor concerned; current passes through the base of the transistor to ground. When there is no conductivity on either probe, solenoid valve 24 is energized to pass pressure fluid from supply line 23 into power cylinder 16.

The latching circuit 35 includes a transistor T3 and silicon controlled rectifier SCR for amplification, power being supplied through resistor R10, with a resistor R11 leading to ground. The function of the latching circuit is to hold the solenoid valve 24 energized, following energization via resistor R9 when pulp drops below the low probe, until the pulp reaches the high probe to deenergize such solenoid valve. A protective diode D connected in parallel with the solenoid valve 24 shunts any high current surges when such valve is de-energized.

Whereas the invention is here illustrated and described with respect to certain preferred forms thereof, it is to be understood that other forms are possible.

We claim:

1. Apparatus for sampling a flowing stream of material, comprising a conduit for supplying the stream of material, said conduit having a discharge end portion that is shiftable in position from side-to-side to direct stream discharge to alternate locations; screen means pivotally attached to said discharge end portion of the conduit and pivotally anchored above said alternate locations to assume a screening position over a sample-receiving one of said locations when stream discharge is to that location and to assume a dumping position for the oversize-retaining surface of the screen means when stream discharge is to a sample-rejecting one of said locations; means for shifting said conduit end portion and the thereto attached screen means from side-to-side over said alternate locations; and means for bringing travel of said screen means to an abrupt halt in its said dumping position for dislodging and dumping retained oversize material from the said oversize-retaining surface.

2. Apparatus according to claim 1, wherein the alternate locations are provided by side-by-side compartments of a material-receiving tank, one of said compartments being adapted to receive samples and to pass them on to analytical equipment and the other of said compartments being adapted to receive and to pass on the said stream of material as well as the screen-oversize material dumped from said screen means.

3. Apparatus according to claim 2, wherein one end of the screen means is pivotally anchored to the tank between the compartments, and wherein linkage means pivotally secures said screen means, intermediate its ends, to the discharge portion of the conduit.

4. Apparatus according to claim 3, wherein there are additionally provided means for sensing the level of material in the sample compartment, and means under the control of said sensing means for switching the discharge portion of the conduit from compartment to compartment.

5. Apparatus according to claim 3, wherein the pivotal anchorage of the screen means to the tank comprises brackets depending within the tank from anchorage to 6 the top of mutually oppositeink walls. the discharge portion of the conduit from location to loca- 6. Apparatus according to claim 5, wherein the brackets D. have hook formations at their upper ends for hooking References Clted over the tank walls, and the screen means is pivotally UNITED STATES PATENTS mounted in and between the lower ends of said brackets. 5 2 336 539 12/1943 Gilbert 7. Apparatus according to claim 1, wherein there are 2:518:574 8/1950 Skopecek 73 422 XR additionally provided means for sensing the accumulation 2,950,724 8/1960 Roederer 73 421 XR of material in the sample-receiving location, and means under the control of said sensing means for switching LOUIS PRINCE Primary Examiner 10 H. C. POST III, Assistant Examiner 

